Apparatus for sealing and folding flanged edges of containers



R. J. LEE 3,

APPARATUS FOR SEALING AND FOLDING FLANGED EDGES 0F CONTAINERS Aug. 3,1965 2 Sheets-Sheet 1 Griginal Filed Oct. 26, 1960 4 9M w w w W K? m 2Mmi 3 2% w. 1 4 7 M w m wfi x 4 0w J w INVENTOR. Ric/20rd J. L ee R. J.LEE

Aug. 3, 1965 APPARATUS FOR SEALING AND FOLDING FLANGED EDGES OFCONTAINERS 2 Sheets-Sheet 2 Original Filed Oct. 26. 1960 INENTOR.Richarod. L ee :0 am/m United States Patent 3,198,683 APPARATUS FGRSEALlNfi AND FOLBING FLANGE!) EDGES 0F CGNTAINERS i. ichard J. Lee,Midland, Mich, assignor to The Dow Chemical Company, Midland, Mich, acorporation of Delaware Original application (lot. 26, 196%, Ser. N65,992, now Fatent No. 3,160,999, dated Dec. 15, 1964. Divided and thisapplication Sept. 8, 1964, Ser. No. 394,935

8 Claims (Cl. 156-485) This is a division of application Serial No.65,092, filed October 26, 1960, now Patent No. 3,160,999 grantedDecernber 15, 1964.

This invention relates to a method for sealing and folding flanged edgesof thermoplastic containers made from resinous organic polymers, and toa container made thereby.

Containers of similar type generally are fabricated with a protrudingflange at the joint, which joint is not only unsightly, but often is ofinferior strength. The containers made according to the method of thepresent invention have a sealed flange which is hot pressed against anoutside wall of the container, thus making a smooth looking joint, andone which has high strength potential. The method further lends itselfto speed-up of sealing process, as heating and cooling are done atseparate locations in the same die means, thus eliminating need forcycling dies.

Briefly, the method of the invention involves placing two preformedhalves of a container in a die means, heating flange portions of thehalves, and forcing the heated flange portions together to form a joint.The joined halves are then moved downwardly in the die means, whereuponthe sealed flanges are folded into engagement with an outside wall ofone of the container halves. After the flange folding operation, thecontainer is moved downwardly in the die means to a cooling area whereinthe folded joint is cooled and set, following which the container isremoved from the die means. The method lends itself to high volumeoperation, and the fabrication of thermoplastic containers having highstrength joints.

Themain object of this invention is to provide an improved method forsealing and folding flanged edges of thermoplastic containers.

A more specific object of this invention is to provide an improvedmethod for sealing and folding flanged edges of thermoplastic containersto produce a smooth joint, and one which has high strength potential.

Still another object of this invention is to provide an improved methodfor fabricating containers of two or more joined parts, which methodlends itself to high volume operation, and is further characterized bysimplified cycling procedures.

These and further objects and features of the invention will become moreapparent from the following description and accompanying drawingswherein:

FIG. 1 is a cross-section view of container halves and a die means usedfor fabrication of a container according to the method of the inventionand illustrating an initial step in the method;

FIG. 2 is the same but illustrating a flange sealing step in saidmethod;

FIG. 3 is the same but illustrating a sealed joint cooling step in saidmethod;

FIG. 4 is an exterior view of a container which has been fabricatedaccording to the method of the invention;

FIG. 5 is a cross-section view similar to that of FIG. 1, but showing aslightly modified fabricating procedure; and

FIG. 6 is an exterior view of a container made in the manner of the FIG.5 illustration.

Referring now to FIGS. 1 to 4, the numeral it? identi- 3.,l93fi33Patented Aug. 3, 1965 fies a cylindrical container having a sealed andfolded joint 12 made according to the method of the invention. Thecontainer is formed of two halves l4 and 16, which as best seen in FIG.1, are cupdike portions of similar diameter and having integral lips, orflanges 18 and 20 respectively, each of said flanges lying in a planenormal to that of the vertical axis shown. The container half 16 may beformed with an opening 22, if desired.

A die means, which may be utilized for practicing the method of theinvention, includes an upper die 24, and a lower die assemblage 26. Theupper die 24 is provided with a circular opening 25, of substantiallarger diameter than that of the container half 14-, and has at itslower extremity a reduced diameter jaw, or heating portion 39, definedin part by a downwardly extending tapered surface 32. Means are providedto heat the lower portion of the die 24, such being, for example, aninternal passageway 34 in which a heating medium may be circulated. Insuch manner, the heating portion 30 may be heated to the extentnecessary for heat sealing a flange joint, as will hereinafter bedescribed.

The lower dieassemblage includes a heating die 36, a heat insulatingsection 38, and a cooling die 46 which is separated from engagement withthe heating die 35, by the insulating section 38. The heating die 36 isprovided with a jaw, or heating portion 42 defined by an opening ofslightly larger diameter than that of the container half 16, and adownwardly and outwardly extending tapered surface 44 leading from saidopening which terminates in a smooth curve ending at the lower surfaceof the die 36. Means are provided to heat the upper portion of the die,such being, for example, an internal passageway 46 in which a heatingmedium may be circulated. In such manner, the heating portion 42 may beheated to the extent necessary for heat sealing a flange joint, as willhereinafter be described. The insulating section 38, which is interposedbetween the heating die 36 and cooling die 4-9, has an opening 48 withan internal diameter which is generally the same as the diameter at thelower end of the heating die 36. Actually, the insulating section 38serves only as a heat insulating spacer, and the diameter 48 need onlybe sufiicient to provide ample clearance as the container movestherethrough. The cooling die 46 has an opening 50 of diametersubstantially equal to the minimum diameter of the heating portions 3t)and 42, the upper region of said opening 5t) serving as a coolingstation and having a curved portion 52. Means are provided to cool thedie 4%, such being, for example, an internal passageway 54 in which acooling medium may be circulated.

Means (not shown) are provided for causing relative movement between theheating die 24 and die assemblage 26, whereby the flanges 1S and 20 maybe pressed together to form a heat sealed joint extending about theperiphery of the container halves 14 and 16. Container moving means, aslater shown and described herein, are adapted for moving the containerthrough the die assemblage 26, after formation of the container joint.

The apparatus above described may be utilized to practice the method ofthe invention in the following manner. As seen in PEG. 1, the containerhalves l4 and To have been placed in the die 24 and die assemblage 26respectively, with the flanges 18 and 20 in juxtaposition.

The die 24 is next moved downwardly (FIG. 2) whereby the flanges 18 and20 are securely clamped together between the heating portions and 42,which, under given pressure and temperature conditions depending uponcertain variables such as the material of the container, thickness, andarea of the flanges, will result in the heat sealing of the flanges.

The die 24 is next moved upwardly to release the sealed flanges l8 and2%), following which container moving means (not shown) will move thecontainer downwardly in die assemblage 26. Such movement will cause thesealed flanges l8 and 2% to be folded upwardly against the container sothat a cross-section taken through the joint 12 thus produced wouldinclude the flange 2%, flange 18 and the body of the container half 14.Downward movement continues until the container joint 12 is brought intocontact with the cooling die at), as shown in FIG. 3. The container isheld in the cooling die until the joint 12 is below heat distortiontemperature, after which the container may be moved downwardly out ofthe die asset blage 26.

In utilizing the apparatus to practice the method of the invention,differential pressure may be applied to the container to force the joint12 outwardly during the folding and cooling thereof. In addition, thecomponents of the die assemblage 2% may be of such proportions so that acontainer may be in joint cooling position while the flange of the nextcontainer are being heat sealed.

A container representing a modified embodiment which may be produced bythe method of the invention, is shown in FIGS. and 6. The chiefdifference between the embodiment illustrated in the latter figures, andthat above described, is that the container flanges are pressed from anangle of 60 instead of 90 as in the container made in the dies of FIGS.1 to 3.

As seen in FIG. 5, a heating die 6! has a heating portion 62 at thelower end which provides for an angle of approximately for a flange 64of a container half 66, relative to the body of the container half. Aheater die assemblage 68, has a heating die 7%, which provides for anangle of approximately 30 for a flange 72 of a container half '74relative to the body of the container half, as shown. The die assemblage63 includes an insulating section 76 as well as a cooling die 78, all ofwhich provide the same functions as the equivalent components describedin connection with the first embodiment. A passageway means 89 isprovided in heating die 66 for circulation of a heating medium, and apassageway means 82 is provided in heating die it? for like purpose,while passageway means 84 is provided in the cooling die '78 forcirculation of a cooling medium. A completed joint 86 is shown on afinished container 88. It will be found that the sloped flanges make itsomewhat easier to fold the flanges against the body of the containerduring the folding operation.

Container moving means, as previously mentioned hereinbcfore, mayconsist of a plunger assembly 90, which is of similar diameter to thatof the container, and which is arranged for downward movement in thejoint forming dies. Other means, such as a suction cup arrangement (notshown) may be movably mounted to contact and adhere to the body of thecontainer 101' pulling it through the die assembly, if desired.

A pressure differential means, as also previously mentioned for forcingthe folded flange against the heating and cooling dies, may consist of astopper 92 which may be moved into the hole of the container, and airpressure conducted by a flexible hose 94 can be admitted to thecontainer. Such arrangement will allow air pressure to be maintained inthe container as it is being moved through the folding and coolingoperations. For containers which have no hole, air at atmosphericpressure may be trapped in the container, and the entire folding andcooling die assemblage can be placed under reduced air pressure as thecontainer is moved therethrough.

The material of the container may be any resinous organic polymer whichwill allow sealing or bonding of the flange portions under reasonabletemperature and pressure conditions. For example, polyethylene, andpolystyrene have been found satisfactory for use in the method of theinvention. In lieu of heat sealing, adhesives can be used such aslatexes of styrene or butadene, or other heat activated adhesives orotherwise which are commonly used with the particular resinous organicpolymer being employed. As an alternative, a solvent for the plastic canbe used, for example, polystyrene flanges can be moistened by brushingwith perchloroethylene to soften them, following which they may then bepressed together. It may be found that the heat sealing method ispreferable.

From the foregoing, it will be evident that the disclosed method willsatisfy the objectives hereinbefore set forth.

The foregoing description has been given in detail without thought oflimitation since the inventive principles involved are capable ofassuming other forms without departing from the spirit of the inventionor the scope of the following claims.

What is claimed is:

1. Apparatus for forming folded flange edge thermoplastic containerscomprising, a heating die means formed of two halves which are providedwith heated surfaces movable toward each other to heat seal juxtaposedflanges of a container, said die halves each being formed with anopening of slightly larger size than the size of a container to beprocessed in the apparatus, a cooling die means arranged in axialalignment with the heating die means, said cooling die means beingformed with an opening substantially equal to the size of the opening ofthe heating die means, and a heat insulating spacer arranged between theheating die means and the cooling die means, said spacer having a sizeno less than the diameter of the heating die means.

2. Apparatus according to claim 1, wherein the halves of said heatingdie means are each formed with portions tapering toward the opening ofthe respective die half.

3. Apparatus for sealing and folding flanged edges of a thermoplasticcontainer comprising an upper die and a lower die assemblage, said upperdie assemblage being provided with a circular opening of a largerdiameter than said container and having a reduced diameter jaw structureon its lower extremity, and means to heat such structure, said lower dieassemblage being provided with an upper heat sealing die having asimilar opening as and axial to said circular opening of said upper dieassembly and having a reduced diameter jaw structure on its upperextremity and means to heat such die and jaw structure, said lower dieassemblage also being provided with a cooling die and an insulatingsection interposed between said cooling die and said heat sealing die,each having a circular opening with a larger diameter than saidcontainer therein and means to cool said cooling die, and means forcausing relative movement between the upper die assemblage and the lowerdie assemblage whereby the flanged edges of said container may bepressed together to form a heat sealed joint.

4. The apparatus of claim 3 having, in addition, container moving meansadapted for moving the container from the lower die assemblage afterformation of the container joint.

5. The apparatus of claim 3, having, in addition, container moving meansadapted for moving the container through the lower die assemblage andpressure differential means for forcing the folded flange against theheating and cooling means of said die assemblages.

6. Apparatus for sealing and folding flanged edges of a thermoplasticcontainer comprising an upper die and a lower die assemblage, said upperdie assemblage being provided with a circular opening of larger diameterthan said container and having a jaw structure at its lower portionwhich provides for an angle of approximately 30 for one of the flangededges of said container and means to heat such structure, said lower dieassemblage being provided with an upper heat sealing die having asimilar circular opening as and axial to said circular opening of saidupper die assemblage and having a jaw structure at its upper portionwhich provides for a mating angle of approximately 30 to said jawstructure of said upper die assemblage and means to heat such die andjaw structure, said lower die assemblage also being provided with acooling die and an insulating section interposed between said coolingdie and said heat sealing die, each having a circular opening with alarger diameter than said container therein and means to cool saidcooling die, and means for causing relative movement between the upperdie assemblage and the lower die assemblage whereby the flanged edges ofsaid container may be pressed together to form a heat sealed joint.

7. The apparatus of claim 6 having, in addition, container moving meansadapted for moving the container through the lower die assemblage afterformation of the container joint.

8. The apparatus of claim 6 having, in addition, con- 5 tainer movingmeans adapted for moving the container through the lower die assemblageand pressure diiferential means for forcing the folded flange againstthe heating and cooling means of said die assemblages.

References Cited by the Examiner UNITED STATES PATENTS 2,293,142 8/42Johnson 93-391 2,302,846 11/42 Farmer 53-373 2,737,090 3/56 Nordquist93-551 3,152,944 10/64 Mojonnier et a1 156-498 FRANK E. BAILEY, PrimaryExaminer.

3. APPARATUS FOR SEALING AND FOLDING FLANGED EDGES OF A THERMOPLASTICCONTAINER COMPRISING AN UPPER DIE AND A LOWER DIE ASSEMBLAGE, SAID UPPERDIE ASSEMBLAGE BEING PROVIDED WITH A CIRCULAR OPENING OF A LARGERDIAMETER THAN SAID CONTAINER AND HAVING A REDUCED DIAMETER JAW STRUCTUREON ITS LOWER EXTREMITY, AND MEANS TO HEAT SUCH STRUCTURE, SAID LOWER DIEASSEMBLAGE BEING PROVIDED WITH AN UPPER HEAT SEALING DIE HAVING ASIMILAR OPENING AS AND AXIAL TO SAID CIRCULAR OPENING OF SAID UPPER DIEASSEMBLY AND HAVING A REDUCED DIAMETER JAW STRUCTURE ON ITS UPPEREXTREMITY AND MEANS TO HEAT SUCH DIE AND JAW STRUCTURE, SAID LOWER DIEASSEMBLAGE ALSO BEING PROVIDED WITH A COOLING DIE AND AN INSULATINGSECTION INTERPOSED BETWEEN SAID COOLING DIE AND SAID HEAT SEALING DIE,EACH HAVING A CIRCULAR OPENING WITH A LARGER DIAMETER THAN SAIDCONTAINER THEREIN AND MEANS TO COOL SAID COOLING DIE, AND MEANS FORCAUSING RELATIVE MOVEMENT BETWEEN THE UPPER DIE ASSEMBLAGE AND THE LOWERDIE ASSEMBLAGE WHEREBY THE FLANGED EDGES OF SAID CONTAINER MAY BEPRESSED TOGETHER TO FORM A HEAT SEALED JOINT.